1. Field of the Invention
The present invention relates to a solid-liquid separating filter medium for sewage, waste water, etc. More particularly, the present invention relates to a solid-liquid separating filter medium of sufficient filtering ability for sewage, waste water, etc. which can be prepared easily and is repeatedly usable by back washing without difficulty when the filter medium is clogged due to long-term service thereof.
2. Prior Art
Floating sludge in sewage and waste water has been conventionally removed by filtration, centrifugal separation, pressurized floatation, solidification by the use of a coagulant, and the like.
In the case of filtration above all, a filtration film is generally used. It is necessary, however, to laminate a number of filtration films instead of a single use thereof so as to increase the filtration effect, while preparation of such laminated films is rather troublesome. Other filter media other than the films used for filtering sewage, waste water, etc. include various kinds of materials such as cloth, sand, ceramics, porous medium and the like. These media tend to cause clogging during long-term service, which are hardly reused by back washing.